ML19332A712
| ML19332A712 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 07/24/1980 |
| From: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | William Jones OMAHA PUBLIC POWER DISTRICT |
| References | |
| NUDOCS 8009180147 | |
| Download: ML19332A712 (1) | |
Text
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July 24, 1980 q
Docket No. 50-285 Omaha Public Power District ATTN:
W. C. Jones, Division Manager -
Production Operations 1623 Harney Street Omaha, Nebraska 68102 Gentlemen:
The enclosed II Bulletin No. 80-18, is forwarded for action.
A written response is required.
In order to assist the NRC in evaluating the value/ impact of each Bulletin on licensees, it would be helpful if you would provide an estimate of the sanpower expended in conduct of the review and preparation of the report (s) required by the Su11stin.. Please estimate separately the manpower associated with correc-tive actions necessary following identification of problems through the Bulletin.
If you desire additional information regarding this natter, please contact this office.
Sincerely, h
Al
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' W. cV$/s/tb Karl 7.'Seyfrite Director
Enclosures:
1.
List of Bulletins Recer.tly Issued-cc:
S. C. Stevens, Manager.
Forr Calhoun Station.
Post Office Box 98 Fort Calhoun, Nebraska 68102 800918.0 M g-
SSINS No.: 6820 Accession No.-
UNITED STATES 8005050062 NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C. 20555 IE Bulletin No. 80-18 Date:
July 24, 1980 Page 1 of 3 MAINTENANCE OF ADEQUATE MINIMUM FLOW THRU CENTRIFUGAL CHARGING PUMPS FOLLOWING SECONDARY SIDE HIGH ENERGY LINE RUPTURE Description of Circumstances:
Letters similar to the May 8, 1980. notification made pursuant to Title 10 CFR Part 21 (enclosure) were seat from Westinghouse to a number of operating plants and plants under construction (list, within enclosure) in early May, 1980.
The letters and the enclosed "Part 21" letter contain a complete description of the potential problem summarized below. The letters indicated that under certain conditions the centrifugal charging pumps (CCPs) could be damaged due to lack of minimum flow before presently applicable safety injection (SI) termination criteria are met. The particular circumstances that could result in damage vary somewhat from plant to plant, but involve unavail-ability of the pressurizer power operated relief valves (PORVs), with operation of one or more CCPs repressurizing the reactor during SI following a secondary system high energy line break. Since the SI signal automatically isolates the CCP mini-flow return line, the flow through the CCPs is determined by the individual pump characteristic head vs. flow curve, the pressurizer safety valve setpoint, and the flow resistances and pressure losses in the piping and in the reactor core. That minimum flow may not be adequate to insure pump cooling, and resulting pump damage could violate design criteria before current SI termination criteria are met.
Westinghouse recommends that plant specific calculations outlined in the letter (enclosure) be performed to determine if adequate minimum flow is assured under all conditions. If adequate minimum flow is not assured, Westinghouse recommends specific equipment and procedure modifications which will result in adequate minimum flow. The recommended modifications assure availability of the necessary minimum flow by assuring that the mini-flow bypass line will be open when needed, but will be closed at lower ypass line closure might be DUPLICATE DOCUMENT Entire document previously entered into system under:
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